AERODYNAMIC ANALYSIS OF RAMP TYPE VORTEX GENERATOR ON NACA 2215 AIRFOIL

AERODYNAMIC ANALYSIS OF RAMP TYPE VORTEX GENERATOR ON NACA 2215 AIRFOIL

Nilesh Nahar1 , Manoj Sharma2 , Amit Kumar Jha3 , Rahul Joshi4

1M.Tech student, Design of Mechanical Systems, Department of Mechanical Engineering, Swami Vivekanand College of Engineering, M.P.

2Assistant Professor& HOD, Department of Mechanical Engineering, Swami Vivekanand College of Engineering, M.P.

3 Senior Manager, HAL, Bangalore

4 Associate Professor, Department of Mechanical Engineering, Swami Vivekanand College of Engineering, M.P.

Abstract –

The project is on Aerodynamic Analysis of Ramp TypeVortexGeneratoronNACA 2215Airfoil.Ourgoalis to design and analyze two models namely a ramp type vortexgeneratorona3Dairfoil(Wing)andnormalwing without VG for Reynolds number value 68.47x10^5. We analyzed it to determine whether VG giving an optimum performance in effectively postponing the wing stall angle. After that, we compared the analytical results accordingly. Designing was done by using Ansys Design modeler. NACA 2215 airfoil were chosen on which the vortex generators have been designed and modeled. The design will then be analyzed (CFD) by using ANSYS R20 software.

Key Words: NACA 2215, ANSYS, Reynolds number, Ramp Type Vortex Generator

1. INTRODUCTION

A vortex generator is an aerodynamic device consisting of a small blade usually attached to a lifting surface or airfoil (such as an aircraft wing) or a wind turbinerotorblade.

The vortex generators are installed quite close to the leading edge of the airfoil to ensure steady airflow over the trailing edge control surfaces to ensure the effectivenessofthetrailingedgecontrolsurfaces.

1.1 Working of Vortex Generators

Vortex generators create strong tip vortices that bring in high energy air from the outer nozzle to mix with/replaceslower moving airin theboundarylayer. It reduces the effects of adverse pressure gradients and preventsseparation.

1.2

Allsolidobjectspassingthroughafluidacquireafluid boundarylayeraroundthem,whereviscousforcesarisein thefluidlayernearthesurfaceofthesolid.Boundarylayers can be either laminar or turbulent. A reasonable judgment as to whether the boundary layer will be laminar or turbulentcanbemadebycalculatingtheReynoldsnumber ofthelocalflowconditions.

1.3 Smart Vortex Generators

TheVGcreatesavortexthat,byremovingaportionof the slow-moving boundary layer in contact with the airfoil surface,delayslocalflowseparationandaerodynamicstall, thereby improving the efficiency of wings and control

Fig1.1:Wingwithvortexgenerators

Boundary Layer Separation on An Airfoil with And Without VG’s

Fig1.2:FlowbeforeVGandAfterVG

surfaces such as flaps, ailerons, rudders, and elevators. To achieve this, they are often placed on the exterior surfaces of vehicles or load-bearing surfaces. During steady cruise, most vortex generators create drag and must be retractable. Therefore, intelligent vortex generators need to be implemented. The intelligent vortex generator is based on the profile at launch and at lowspeeds.Andtheyretractwhencruisingathighspeed and altitude. Some concepts for an intelligent vortex generator have already been designed, constructed, and tested.

1.4 Shape Memory Alloys

A shape memory alloy is an alloy that can be deformed when cold but returns to its pre-deformed ("remembered")shapewhenheated.

SMA’s can be used as intelligent vortex generators; they change shapes due to changes in atmospheric temperatureatdifferentaltitudes.

2 METHODOLOGIES

structureofshapememoryalloy

1.5 Pneumatic actuators

Pneumatic actuators are mechanical devices that usecompressedairactingonapistoninsideacylinderto move a load along a linear path. Unlike their hydraulic alternatives,theoperatingfluidinthepneumaticdriveis onlyair,soleaksdonotdripandpollutethesurrounding spaces.

These pneumatic actuators are used to control vortexgenerators.Pneumaticactuatorscanbecontrolled by an altimeter for height measurement and a speedometer for retracting and extending by measuring heightandspeed.

3 CFD MODELLING

Fig1.3:Example

Fig3.1:FlowDomain

The Airfoil design is imported into Workbench Mesh.Thedomainiscreatedingeometryusingthe"draw and create" option. A network is created within a network. The mesh size is varied until the desired Skewness,aspectratio&orthogonalqualityisachieved.

4

This subsection combines the Computational Fluid Dynamic analysis results of a complete analysis of the NACA 2215 airfoil with VG configurations. CFD analysis of the problem, two-dimensional structured mesh with RANSmodelandS-Aturbulence.

Theaimofthe projectisto studythe aerodynamics flow behavior around the wing with Vg at specified heightsof3mmandtoimprovetheaerodynamics.

4.1

Pressure Contours of NACA2215 Airfoil without VG atvariousAoAshownbelow

4.2

ofattack(-2,0,2,4,8,12,14,16,18,20)

Fig3.2:Meshoftheflowdomainwith&withoutVG

RESULTS AND DISCUSSION

Pressure Contours of NACA 2215 Airfoil Without VG

Pressure Contours of NACA 2215 Airfoil of 3mm VG heights

angles

Fig4.1:PressureContoursofwingwithoutVGatvarious

4.3

The lift and drag characteristics of NACA 2215 airfoil with vg 0.3 mm height at different angle of attack (-2, 0, 2, 4, 8, 12, ..………20) along with Reynolds number (68.47x105 )arethreeparametersconsideredinthiscase studyand the simulation is performedfor eachheightof Re and vg. The results obtained from these parameters are shown below in the table column in terms of Cl and Cd.

5 CONCLUSIONS

With the help of Ansys-Fluent CFD software, CFD analysis of aerodynamic performance of a NACA2215 Airfoilwithrampedvortexgeneratoratvariousanglesof attack-2,0,2,4,8,12,..………20degreeswithaReynolds number of 68.47 × 105 using the Spalart-Almaras turbulence model has been done. The results shows that successful delay of flow separation on the NACA 2215 Airfoil with a ramp-type vortex generator as a passive control technique, but not only that it is a pond post. angle of attack but also increased the CL (max) of the NACA2215airfoil.ForRe=68.47×105 (V=100m/s)the VGrampof3mmisshowntobeeffectiveindelayingthe stall angle by 4 degrees and increasing the CL (max) = 1.65.

Itcanbeseenfromabovethatwitha3mmramp,vg is very effective in delaying the angle of attack of a normal NACA2215 Airfoil. Although the value of Cd is slightly higher than that of a normal wing at a higher angle of attack, the Cl/Cd ratio is higher than that of a normalNACA2215wing.

REFERENCES

[1] Mi, H.Zhan, S.Lu, An extended unsteady aerodynamic model at high angle of attack, Aerosp. Sci. Technol,77,2018

[2] Ramanujam G, Ozdemir and hoeijmakers, improvingairfoildragprediction,AIAA,2016

Lift and Drag Characteristics

Re=68.47×105

Fig4.2:PressureContoursofwingwithVGofheight3mm atvariousanglesofattack(-2,0,2,4,8,12,14,16,18,20)

Table4.1LiftandDragcharacteristicsatRe=68.47×105

[3] Schetz,J.A, Boundary Layer Analysis, NASA STI/ReconTechnical Report,93,1993

[4] Drela M, XFOIL Subsonic Airfoil development System,Springer,2016

[5] Wilson.T,KC,R., Lucido,NA., Elbing,B Alexander, ComputationalInvestigationoftheCVG,AIAA,2019